The world would not be the same without the marine transport and shipping industries that make up a significant portion of the world’s ocean maritime traffic. The world is a lot “smaller” than it used to be, and that means businesses around the world now export and ship more goods to their global neighbors in other countries than at any point in history.
Through all of this, residual fuel oils like Bunker C (HFO) and marine fuel oil (MFO) provide the power needed to get the job done.
Marine Fuel Oil: Characteristics
Heavy fuel oil and marine fuel oil are the dominant fuels of choice for these essential business sectors, as they provide the best combination of power and low cost. Marine fuel oils are less expensive than the more refined #2 diesel fuel used on the road. They contain more energy per gallon than these lighter fuels.
In exchange of lower cost and high energy content, the tradeoff comes in that these fuels also have higher levels of harmful inorganic components like sulfur and vanadium. The high levels of metals and sulfur would normally harm car and truck engines. But out on the open water, these heavy marine fuel oils prove to be ideal, as the engines that run on them are larger diesel engines with the ability to handle the higher ash loads the heavy fuel oils produce.
Where there are high levels of sulfur and vanadium in fuel, there are often concerns with corrosion damage of the engines and its associated parts. The sulfur from the fuel reacts with oxygen during combustion and will oxidize in the engine, with the vanadium contributing in a catalytic role.
The resulting SO2 and SO3 emissions gases will combine with water vapor already present after combustion (remember that combustion produces CO2 and water as the byproducts), with sulfuric acid as the result. The sulfuric acid condenses onto metal surfaces as the exhaust gases cool, with corrosion damage as the result. This is bad news for expensive ship engines, fuel systems and exhaust emissions equipment.
Many times it is more cost-effective for ships burning these kind of fuels in heavy, slow-screw diesel engines to prevent corrosion and other fuel issues by additizing the fuel oil with a fuel treatment. But what kind of treatment is best to use? Bell Performance has found that the best maritime fuel oil treatments contain most of the following elements:
Organometallic corrosion inhibitors and neutralizers – to prevent costly and damaging corrosion
Combustion improvers – a combination of organic and organometallic
Surfactants – to remove accumulation of heavy end fallout from the fuel oil and to keep fuel delivery and injection systems clear and functioning at optimal performance
Perhaps the Holy Grail for these large ships is to find something that reduces their regulated exhaust emissions. Large ships have to comply with special rules that dictate what kind of fuel they can burn when they are close to shore. Having to switch from cheaper HFO/MFO to more expensive #2 diesel fuel (because it burns cleaner with less sulfur gases) presents a significant cost for the shipper.
You may be interested in these related posts:
- Marine Fuel Oil: Neutralizing Corrosion In Large Ships
- Marine Transportation Facing Challenges
- Marine Fuel Additives For Commercial Use
This post was published on August 29, 2014 and was updated on July 1, 2020.